Stylist to Brad Pitt: Lose the Beard!

With his scraggly gray beard more unkempt than ever, Brad Pitt looked unrecognizable as he walked through Nice International Airport in France Thursday.

So what's with the out-of-control facial fuzz?

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Pitt, 45, is likely "marking a transition or marking a new stage in his career," says Dr. Alan Peterkin, psychiatrist and author of One Thousand Beards: A Cultural History of Facial Hair.

Peterkin tells Usmagazine.com that a beard allows a man "to change his public face. Most men growing facial hair around his age are being ironic. It's a bit of a wink of the eye; 'I'm not taking this too seriously and nor should you.'"

Angelina Jolie's man -- who has often sported facial hair -- also may be "tired of being a part of one of the most beautiful couples in the world. He wants to try a new look."

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Although Peterkin tells Us the look may appear "desperate on another man's face," Pitt's facial structure makes it work. "With a face like Brad's, you can do almost anything," he tells Us. "It is such a well put-together, symmetrical face."

But celebrity hairstylist Sally Hershberger isn't a fan.

"I don't love gray facial hair, especially on someone as handsome as Brad," she tells Us.

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Although she says "he has some reasoning behind his look," she suggests that he trim it and dye it all brown.

Still, she tells Us, "I would prefer for him to shave it completely."